Kearns-Sayre syndrome (KSS) is caused by large deletions of mitochondrial DNA. Patients with KSS usually exhibit signs and symptoms before the third decade of life, with ophthalmoplegia, ptosis, pigmentary retinopathy, and one of the following: cardiac conduction defect, cerebellar dysfunction, or elevated CSF protein (>100 mg/dl). Patients may also have heterogeneous multisystemic disorders. The mutant mitochondrial DNA is usually detectable in muscle but not in blood. Therefore if KSS is suspected, a muscle specimen is recommended. In general, KSS is sporadic. However, in rare cases, if the deletion is present in blood and/or with a partial duplication, the deletion mutant may be transmitted to offspring. Reasons for Referral:
Testing Methodology:Please refer to Mitochondrial DNA Screen (Point Mutations and Deletions) |